With left-handers Matt Harrison and Martin Perez possibly done for the season, the Texas Rangers are looking internally to fill their spots.

They recalled right-hander Nick Tepesch before Wednesday’s game to replace Perez, and will insert rookie Nick Martinez back into the rotation to take Harrison’s spot.

General manager Jon Daniels said the team could go outside the organization and make a trade at some point, but isn’t looking at that avenue yet.

Tepesch and Martinez will join a rotation featuring Yu Darvish, Robbie Ross and Colby Lewis. Darvish, Ross and Lewis are expected to start (in that order) this weekend against Toronto.

The Rangers should have more options soon, too, with Joe Saunders (stress fracture in left ankle), Tanner Scheppers (right elbow inflammation) and Derek Holland (left knee surgery) progressing well in their rehabs.

Saunders starts Thursday for Triple A Round Rock in Iowa, Scheppers has started throwing off a mound and Holland continues to throw live batting practice in Arizona.

But there’s no sugar-coating Wednesday’s news, the biggest blow the Rangers have received in a year full of injuries.

“Just the sheer number of injuries is startling,” general manager Jon Daniels said. “We’ve had a combination of everything. … Nobody is crying for us and we’ve got other guys prepared to step in. But you feel for the players. It’s definitely a challenge.”

Harrison, who underwent two surgeries on a herniated disk more than a year ago, was diagnosed with spondylolisthesis, a back condition that causes significant nerve irritation on the vertebra. It could require him to undergo spinal fusion surgery, a career-threatening procedure.

The other option for Harrison is to live with it and try to pitch through it, although it’s unknown how difficult that would be.

Perez, meanwhile, was diagnosed with a partial tear in his ulnar collateral ligament in his left elbow. He is weighing a couple options as well. He can try and rehab it, which would sideline him for approximately three months. Or he can undergo Tommy John reconstructive elbow surgery that would cost him the rest of this season and part of next.

Roster moves

With an inconsistent rotation of late, the Rangers’ bullpen has been taxed daily.

They went into Wednesday’s game having thrown 57 2/3 innings over the previous 15 games and have thrown the fourth-most innings (130 2/3) in the American League.

That’s why the Rangers purchased the contract of right-hander Scott Baker and recalled right-hander Miles Mikolas from Triple A Round Rock.

Baker gives the team another long reliever. He allowed two runs over 5 1/3 innings in a relief appearance against the Rockies on May 7, but was designated for assignment the following day. He cleared waivers and could have taken free agency, but accepted an assignment back to Round Rock.

The 32-year-old liked the idea of staying with a contending team and close to his hometown of Shreveport, La.

“It just didn’t make sense to go anywhere else,” Baker said.

Mikolas, meanwhile, had a 3.38 ERA over eight appearances with the Express.

The Rangers designated right-hander Justin Germano for assignment to clear a spot for Baker. Mikolas was added to the team when Harrison was put on the DL.

Briefly

• Infielder Donnie Murphy, on the DL with a strained neck, is scheduled to begin a medical rehabilitation assignment with Round Rock on Thursday in Iowa.
• Shin-Soo Choo reached on a hit by pitch Tuesday, his sixth of the season. Since 2011, Choo has been hit by pitch 52 times, most in the majors.
• Nick Tepesch became the 22nd pitcher used by the Rangers on Wednesday. That’s the most pitchers used by a single team in the majors.